Engine/Transmission (1998.5 - 2002) We had a real strange problem.....

[Pakrat]

Greetings !!

We were on vacation heading to Las Vegas - crossed the Mojove Desert and ended our day in the little town of Yermo, Ca. It was pretty hot that day-3/21, about 95 degrees. We stopped at a campground and while my wife got us registered, I stayed in the truck and let it cool down. Pulled into our campsite and when we got the 5th wheel where we wanted it, I shut the truck down. Water temp was now 190 and EGT read 300. When I started the truck about 15 minutes later, it would hardly run... . sounded like air in the lines. Could barley drive it and blew lots of blue smoke. Couldn't do much with it then because it was so hot under the hood, so we went out to eat - another couple was with us. Came back and I started it and it ran like nothing was ever wrong????? Any body have any idea what happened? The first thing I thought of was fuel pump but my friend thinks it was so hot, it boiled the fuel and did a vapor lock on me. This ever happen to anybody else?

Thanks for any help or suggestions... ... .....

Larry

 

[Texas Diesel]

Cycle your ignition key 3 times and watch the odometer, it will display any fault codes. Post any you find here, someone canlook them up in a Dodge book or you can look up generic codes on the net.



My 01 did that once after a hard pull but only ran rough for a couple of seconds

 

[Gary - K7GLD]

The vaporlock theory sounds most likely to me...



You *DO* have guages, and monitor fuel pressure, RIGHT?

 

[RowJ]

PAKRAT

Had what I called a very rough idle after a hard run from Dallas to Phoenix at 9200 lbs, non stop, over 80 degrees. Didn't even shut it off - had a drum of diesel fuel and a DC pump with me for fill ups. Checked into motel, cleaned up and started out to dinner - very rough running. I checked for codes - none. I ate at motel and in the morning, it ran fine! Never happened again ??? That was 3,000 miles ago.

 

[Pakrat]

Thank you for the help - - Code came up P 1693. Haven't got a clue what that means.

Gary, I do have EGT and boost but no fuel pressure gauge - - Guess maybe I should get one. I didn't think a fuel injected engine would vapor lock but maybe they will... ... .

Thanks again for your help guys - I do appreciate it.....

 

[Ncostello]

I don't think you could vapor lock a diesel if you put a propane torch on the fuel line. You'd have to boil it to the point of its vapor pressure being higher than surrounding pressures. Gasoline is easier to boil... yet not easy to do either with fuel pumps being in the tank now a days. That and the cooling effect of constantly moving fuel from re-circulation would make it hard even more so. Of course the problem you had is real so something is up.

 

[Gary - K7GLD]

What IS the boiling point of diesel fuel?

 

[Ncostello]

From memory in asphalt lab in college... the boil point of gasoline is something like 100F and diesel fuel 350F. I could be wrong.

 

[RowJ]

PAKRAT

GO to FAQ's under 24 Valve section for ALL codes, thanks to Tim Taylor!

 

[rholcom2]

Put a fuel pressure gauge on it Immediately!!! I think fuel pressure is as big of an issue as the KDP!!!



Just my opinion

 

[Pakrat]

Thanks to all for your replys. I found the codes and will get a fuel pressure gauge. Larry

 

[jelag]

Just a couple of thoughts... ...



1 - vapor locking in gas engines was from the fuel in the float bowl boiling off and entering the intake system... . also the boiled off fuel would leave pressure in the lines and the old fashioned fuel pump mounted on the engine wouldn't function..... once the fuel cooled all was fine...



2 - current equipment has a pump either in the tank, on the frame rail or on the engine that pushes cool fuel to the injection system..... (fuel injection, hp pump... what ever). This cooler fuel with some of the fuel always returning to the tank has prevented this problem... .



3 - diesel does boil at a higher temperature like mentioned above



4 - go after the pump and put a fuel pressure gauge as mentioned above... .



Jim